SFTP is just FTP over SSH... Also, FTP is essentially one small step away from code execution, even on a secure network it's better to use SFTP

SSH isn't many things, it's one connection type through which you can do many things. You can't simply cat a file over without being able to handle the throughput gracefully, otherwise you'd have to design a new layer to do exactly the same thing. The same for reading files, if it can't gracefully spit out 10k lines in a second you couldn't handle output

And if you can do all that, why not allow VIM over the same connection? You're already going to have to manage the terminal session, why not fully reflect a terminal?

FTP is absolutely not the answer, but a server that will conditionally serve files as well as conditionally accept uploads is far more secure. The same for everything... If you want to manage users, instead of allowing remote code execution you should use an API to perform predefined tasks

SSH isn't meant for security or production use, it's meant for power and flexibility. It's generally deactivated by default for a reason, but it's included for a reason too. It's just really damn useful